Repeater Maintenance / Repair at Elephant Mountain

13 May 2017
Repair trip
N5HYD

Short info:
1: A.C. to D.C. power issue found. Did a short-term repair.
2: 147.020 Local Repeater now back on-line, unless the noise returns.
3: I may have fixed the Weather Alert receiver. Also fixed an issue where I forgot to include the Presidio are alarms in the decode list.
Long info:
• HUB REPEATER:
o Hub Repeater had a strange ‘square wave’ sounding noise that started shortly after the system was in use, and slowly became more pronounced as it went.
Temporary swap to a spare Hub Repeater showed no change.
Problem immediately went away when I turned off the A.C. to D.C. switching power supply and bypassed the A.C. surge protection.
Decided to leave the Hub Repeater as-is.

• LOCAL REPEATER:
o Was in disable due to the TX interfering with the RX. I’m hoping it may be related to the D.C. power interference issue noted below.
Enabled Local Repeater.

• POWER SYSTEM:
o ‘Square wave’ noise on Hub Repeater went away just as soon as I unplugged the Power System from the A.C. socket on the wall.
Removed rack mounted A.C. surge protection.
Removed A.C. to D.C. switching power supply. Replaced with a small (15 amp) supply that was left on-site.
o Tested two DEKA 12AVR-145LLPS backup batteries with test set. 60%.

• WEATHER RECEIVER:
o Presidio area alarms not being decoded.
Discovered that I had forgotten to enable them the last time I uploaded the personality
Enabled Presidio area alarms and uploaded the changed personality in the Weather Receiver.

o Possible drop-out during audio portion of weekly test.
Tried to use computer-Icom IC-92 test system that worked at the house on my desktop WX radio.
Unable to get it to work. I may need to actually send the tone audio to a TP-1 on the motherboard but was unable to find TP-1.
Decided to save issue for another day.